Improved Repetitive Control with Model-Assisted Extended State Observer for Optoelectronic Tracking System

The optoelectronic tracking system is a high-precision tracking and positioning device. The uncertainties and disturbances exist in the working process, especially on the moving optoelectronic platforms in recent years. To sufficiently achieve the required motion performance, the suppression of disturbances and the robustness against uncertainties are of increasing importance. In this paper, we propose an improved repetitive control (IRC) method with model-assisted extended state observer to reject periodic and non-periodic disturbances. This two-degree-of-freedom control framework is used with one degree to further estimate and eliminate broadband disturbances and the other to further reject periodic disturbances. IRC can mitigate the magnitude amplification of the non-periodic disturbances caused by conventional repetitive control (CRC). And it only requires the error, input, and output signals of the system without depending on the accurate model parameters. Finally, the effectiveness of the proposed method is verified by simulation and experiment, and the improved performances on estimation accuracy and disturbance suppression are compared in the tip-tilt mirror system.